hi all..so i'll be presenting my problem in form of an example here:

lets say i have a website(60 pages), and i want to promote it for keyword "A". i have a domain name which also highlights "A".

but whole website is not about "A" ("A" is highlighted only on 5 pages), in fact pages are divided into sub parts of "A" (say types of A, but substantially different), say "B" (20 pages), "C" (20 pages), &"D" (15 pages).

now the question arises. should i promote pages on B,C,D for keyword "A", or i should promote them for their own content keywords.

if i promote pages on "B" for keyword "B", how is that going to affect whole website ranking?

hope the problem is clear , please help! because based on your advices, i'm gonna start my activity.